According to research literature, humor inside the staff-patient interaction seems to be significant in the area of forensic mental healthcare. However, existing literature on the subject is limited. Therefore, the aim of this study was to explore the characteristics of the use humor by forensic mental health staff members in interactions with forensic mental health inpatients. The study included 32 forensic mental health staff members, used 307 hours of participant observations, 48 informal interviews, and seven formal semistructured interviews. Outcomes identify four themes concerning the conveyance of power to, from, and between forensic mental health staff and patients as they interact: (a) "the informal use: the human-to-human approach," characterized by an informal use of humor and without any reference to mental health issues; (b) the "formal use of humor: the staff-patient approach," characterized as formal with a view on the patient as mentally ill, unable to understand humor, and with the aim of using humor to prevent conflicts or negative behavior; (c) "protest against requested care: the human-patient approach," characterized by the use of humor as a protest against requested care; and the use of (d) "inadequacy humor: the staff-human approach," characterized by the use of inadequacy - humor referring to, for example, patients' physical features. Recommendations and clinical implications are discussed.